fix: added untracked files:

src/AppState.ts

@@ -0,0 +1,37 @@
+import { ISubscriber, Publisher } from "@djledda/ladder";
+import { TrackUnitStickingType, TrackUnitType } from "./TrackUnit";
+
+export type UITool = 
+    | "track-unit-type" 
+    | "eraser" 
+    | "sticking";
+
+export type AppStateEvent = "appstate-tool-select";
+
+export default class AppState {
+    private publisher = new Publisher<AppStateEvent, AppState>(this);
+    selectedTool: UITool = "track-unit-type";
+    activeTrackUnitType: TrackUnitType = "Normal";
+    activeStickingType: TrackUnitStickingType = "lh";
+
+    constructor() {}
+
+    addSubscriber(subscriber: ISubscriber<AppStateEvent>, subscribeTo: Parameters<Publisher<AppStateEvent, AppState>["addSubscriber"]>[1]) {
+        this.publisher.addSubscriber(subscriber, subscribeTo);
+    }
+
+    selectStickingTypePaint(stickingType: TrackUnitStickingType) {
+        this.activeStickingType = stickingType;
+        this.publisher.notifySubs("appstate-tool-select");
+    }
+
+    selectTrackUnitTypePaint(trackUnitType: TrackUnitType) {
+        this.activeTrackUnitType = trackUnitType;
+        this.publisher.notifySubs("appstate-tool-select");
+    }
+
+    selectTool(tool: UITool) {
+        this.selectedTool = tool;
+        this.publisher.notifySubs("appstate-tool-select");
+    }
+}